喷射沉积Mg-12.55Al-3.33Zn-0.58Ca-1.0Nd合金组织与力学性能研究

利用XRD、OM、SEM、TEM研究了喷射沉积Mg-12.55Al-3.33Zn-0.58Ca-1.0Nd合金挤压态的显微组织和合金的力学性能。结果表明:喷射沉积挤压态镁合金主要包含基体α-Mg和Al2Ca相,基体组织为等轴晶,平均晶粒尺寸为3μm;Al2Ca颗粒主要沿镁基体晶界分布,颗粒尺寸在1.0μm左右,并在Al2Ca相中存在孪晶结构;合金的σb、σ0.2、δ分别为450、325MPa,5%。在拉伸断口上存在大量石块状的Al2Ca相,表明合金的断裂方式为沿晶断裂;与经热挤压的铸造AZ91镁合金对比,该合金强度明显提高,但合金塑性降低;合金强度的提高主要来源于合金的细晶强化和Al、Zn对合金的固溶强化,而伸长率降低是由于合金中存在的大量Al2Ca颗粒是沿镁基体晶界分布,导致合金的塑性降低。     

宣钢单喷颗粒镁铁水预处理技术的应用

介绍了单喷颗粒镁铁水预脱硫技术的优势,在正常的铁水条件下,宣钢采用单喷颗粒镁铁水预脱硫技术,镁粉喷吹速率平均4．5kg／min,可保证脱硫扒渣能力110万t／年,达到了规定的终点脱硫效果。     

模铸低碳复合保护渣的开发与应用

本文针对钢锭浇铸时使用中高碳保护渣对钢锭表面增碳的影响,对钢锭进行解剖,研究钢锭中C偏析的情况,证实保护渣增碳是造成钢锭大幅度增碳的主要原因,进而开发低碳复合保护渣。结果表明,使用中高碳保护渣钢锭表面增碳明显,采用开发的低碳复合保护渣能达到降低钢锭表面增碳的效果,从而提升钢锭的轧板质量。     

液态渣在预拌抹灰砂浆中的应用技术研究

在预拌抹灰砂浆中,液态渣有作掺和料和骨料两种方式应用。实验研究了粉磨时间、激发剂对液态渣粉磨性能的影响,以及破碎液态渣部分取代天然砂后的混合骨料颗粒级配对预拌抹灰砂浆各项性能的影响。结果表明:(1)将液态渣粉料取代水泥作为掺和料使用时,粉磨液态渣时加入激发剂可提高其活性,选用1h粉磨时间较为合适。(2)当破碎液态渣替代部分天然砂拌制抹灰砂浆时,破碎液态渣的掺配比例控制在40%左右是可行的。     

The structural and optical properties of ZnO nanowire arrays prepared by hydrothermal synthesis method

ZnO nanowire arrays have been grown on the ZnO film-coated silicon (100) substrates by hydrothermal method, and the deposited nanowires are found to have a uniform size distribution with sharp hexagonal-shaped tips. The structural and optical properties of the nanowires were investigated using atomic force microscopy (AFM), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and cathodoluminescence (CL) techniques. The XRD and SEM results demonstrate that the well-aligned ZnO nanowires are single crystalline structure formed along the c-axis orientation. TEM analysis further confirms that the ZnO nanowires are highly preferred grown along the (002) crystal plane. The spacing between adjacent (002) lattice planes is estimated as 0.52 nm. The optical properties of the nanowires were measured using CL after annealing in oxygen and nitrogen atmospheres at 550 °C for various times. The CL spectra in the visible spectrum exhibit two weak deep-level emission bands that may be attributed to the intrinsic or extrinsic defects. It can be observed that the ZnO nanowires show different optical behaviors after various annealing times. The dependence of the optical properties on the annealing conditions is also discussed.     

Modeling of mechanical response of FRP composites in fire

A thermomechanical model is presented for predicting the time-dependent deflections of cellular FRP slab elements subjected to mechanical loading and fire from one side. The model comprises temperature-dependent mechanical property sub-models for the Young’s modulus, viscosity and coefficient of thermal expansion. Two different thermal boundary conditions were investigated: with and without liquid-cooling of the slab elements in the cells. A finite difference method was used to calculate the deflection at each time step. Deflections resulting from stiffness degradation due to glass transition and decomposition of the resin dominated over those resulting from viscosity and thermal expansion. The predicted total deflections compared well with the measured results over a test period of up to 2 h. The failure mode of the non-cooled specimen could be explained.     

Optimal deployment of multiple passive sensors in the sense of minimum concentration ellipse

In the sense of minimum concentration ellipse, the optimal deployment of multiple passive sensors in bearing-only location system is studied in terms of cut angle. It is found that the optimum cut angle depends only on l, the ratio of the distance between target and the baseline of the two sensors to the baseline length. When l is greater than 0.5, the optimum cut angle can be obtained if the deployment of the target and the two passive sensors is an isosceles triangle with the baseline length as its base side. When l is less than 0.5, the optimum cut angle can be obtained if the target and the two passive sensors are located on the circle with the baseline length as its diameter, that is, the deployment of the target and the two passive sensors being a right triangle. When l equals 0.5, the optimum cut angle can be obtained if the target and the two passive sensors are deployed on an isosceles right triangle. The global minimum value of concentration ellipse can be asymptotically reached by decreasing the ratio l to zero based on these properties of the optimum cut angle.     

基于SSH架构的社区卫生管理系统设计与实现

针对传统社区卫生管理系统开发的不足,基于J2EE企业级应用开发平台,整合Struts、Spring和Hibernate（SSH）开源框架技术,提出了一种多层社区卫生管理信息系统模型,实践表明,该整合框架在构建复杂业务系统中提高了开发效率和系统的可维护性,同时增强了系统的可扩展性。